/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.shardingsphere.sql.parser.postgresql.parser;

import org.antlr.v4.runtime.CharStream;
import org.antlr.v4.runtime.Lexer;

import java.util.ArrayDeque;
import java.util.Deque;

/**
 * SQL lexer base for PostgreSQL.
 */
public abstract class PostgreSQLLexerBase extends Lexer {
    
    private final Deque<String> tags = new ArrayDeque<>();
    
    protected PostgreSQLLexerBase(final CharStream input) {
        super(input);
    }
    
    /**
     * Push tag.
     */
    public void pushTag() {
        tags.push(getText());
    }
    
    /**
     * Judge is tag.
     *
     * @return is tag
     */
    public boolean isTag() {
        return getText().equals(tags.peek());
    }
    
    /**
     * Pop tag.
     */
    public void popTag() {
        tags.pop();
    }
}
